*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
.electrical-equipment-top{
    width: 700px;
    margin: auto;
}
.nav::after{
    display: table;
    content: "";
    clear:both;
}
.nav li{
    list-style: none;
    float: left;
    padding: 10px;
    width: 70px;
    text-align: center;
    cursor: pointer;
}
.nav .active{
    color:#ff5000;
    border-bottom: 2px solid #ff5000;
}
.main>div{
    display: none;
}
.main>div.active{
    display: block;
}
.main .active p:hover{
    color:#ff5000;
}
